/*
 * Copyright (c) 2018, Oracle and/or its affiliates. All rights reserved.
 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
 *
 * The Universal Permissive License (UPL), Version 1.0
 *
 * Subject to the condition set forth below, permission is hereby granted to any
 * person obtaining a copy of this software, associated documentation and/or
 * data (collectively the "Software"), free of charge and under any and all
 * copyright rights in the Software, and any and all patent rights owned or
 * freely licensable by each licensor hereunder covering either (i) the
 * unmodified Software as contributed to or provided by such licensor, or (ii)
 * the Larger Works (as defined below), to deal in both
 *
 * (a) the Software, and
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 * (b) any piece of software and/or hardware listed in the lrgrwrks.txt file if
 * one is included with the Software each a "Larger Work" to which the Software
 * is contributed by such licensors),
 *
 * without restriction, including without limitation the rights to copy, create
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 * Software and the Larger Work(s), and to sublicense the foregoing rights on
 * either these or other terms.
 *
 * This license is subject to the following condition:
 *
 * The above copyright notice and either this complete permission notice or at a
 * minimum a reference to the UPL must be included in all copies or substantial
 * portions of the Software.
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package com.oracle.truffle.dsl.processor.java;

import java.util.HashMap;
import java.util.Map;
import java.util.WeakHashMap;
import java.util.function.Function;
import javax.annotation.processing.ProcessingEnvironment;
import javax.lang.model.SourceVersion;
import javax.lang.model.element.ModuleElement;
import javax.lang.model.element.TypeElement;

final class ModuleCache {
    private static final Map<ProcessingEnvironment, Map<String, ModuleElement>> moduleCacheCleaner = new WeakHashMap<>();

    private ModuleCache() {
        throw new IllegalStateException("Cannot instantiate.");
    }

    static TypeElement getTypeElement(final ProcessingEnvironment processingEnv, final CharSequence typeName) {
        if (processingEnv.getSourceVersion().compareTo(SourceVersion.RELEASE_9) < 0) {
            return processingEnv.getElementUtils().getTypeElement(typeName);
        }
        final Map<String, ModuleElement> moduleCache = moduleCacheCleaner.computeIfAbsent(processingEnv, new Function<ProcessingEnvironment, Map<String, ModuleElement>>() {
            @Override
            public Map<String, ModuleElement> apply(ProcessingEnvironment t) {
                return new HashMap<>();
            }
        });
        final String typeNameString = typeName.toString();
        ModuleElement moduleElement = moduleCache.get(typeNameString);
        if (moduleElement == null) {
            final TypeElement typeElement = processingEnv.getElementUtils().getTypeElement(typeName);
            if (typeElement != null) {
                moduleElement = processingEnv.getElementUtils().getModuleOf(typeElement);
                moduleCache.put(typeNameString, moduleElement);
            }
            return typeElement;
        } else {
            return processingEnv.getElementUtils().getTypeElement(moduleElement, typeName);
        }
    }
}
